OFFSET
0,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (1,1).
FORMULA
G.f.: (3+12*x)/(1-x-x^2). - Philippe Deléham, Nov 19 2008
From G. C. Greubel, Dec 25 2025: (Start)
a(n) = 3*A022095(n).
E.g.f.: 3*(cosh(sqrt(5)*x/2) + (9/sqrt(5))*sinh(sqrt(5)*x/2))*exp(x/2). (End)
MATHEMATICA
LinearRecurrence[{1, 1}, {3, 15}, 40] (* Harvey P. Dale, May 27 2012 *)
PROG
(Magma)
[3*GeneralizedFibonacciNumber(1, 5, n): n in [0..50]]; // G. C. Greubel, Dec 25 2025
(SageMath)
A022381= BinaryRecurrenceSequence(1, 1, 3, 15)
print([A022381(n) for n in range(51)]) # G. C. Greubel, Dec 25 2025
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved